Photostimulated Reaction of Diphenylarsenide and Diphenylstibide Ions with Haloaromatic Compounds by the SRN1 Mechanism. Electron Transfer vs. Bond Breaking of the Radical Anion Intermediate

Article abstract of DOI:10.1021/jo00340a016

Photostimulated reactions of haloaromatic compounds with potassium diphenylarsenide and potassium diphenylstibide were studied in liquid ammonia. 1-Bromonaphthalene and 9-bromophenanthrene reacted with diphenylarsenide ion to give four products: triphenylarsine, diphenylarylarsine, phenyldiarylarsine, and triarylarsine (aryl = 1-naphthyl and 9-phenanthryl); with 2-chloroquinoline as substrate only the straightforward substitution product 2-qiunolyldiphenylarsine was formed. p-Bromoanisole and 4-chlorobenzophenone reacted with potassium diphenylstibide to give four stibines: triphenylstibine, diphenylarylstibine, phenyldiarylstibine, and triarylstibine (aryl = p-anisyl and 4-benzoylphenyl).These reactions are believed to occur by the S_RN1 mechanism with an extra feature of reversible coupling of aryl radicals with arsenide and stibide ions, which causes the scrambling of aryl rings.It is suggested that the low-lying ?^* MO of the quinolyl moiety prevents C-As bond breaking of the radical anion intermediate.